I have a library that has exceeded apples limitation of 100K items - they finally acknowledged that Apple Music items count against that limit - deleting several thousand Apple Music items got me under the limit - so - I shuffle my library and with iTunes Match and Apple Music I expect that it will keep playing when I leave and restart at home when I arrive - home kit setup for this - it doesn’t work - my issue is - when shuffle playing a large library the crossfade does not work - several seconds to minutes between songs - I - dozens of times a day have to say skip the song because no music has played for who knows how long - but - if you wait too long you have to go to the device - either iPhone or iMac and restart music - no rhyme or reason for its behavior - it works best without pauses on the phone in the car - not so much with the iMac at home but it’s all my music shuffled - it frequently takes an inordinate amount of time “loading” before music will start when changing from home to mobile but the biggest issue I have is it loading what appears to be a selected playlist that then gets put back in the library and then pics another playlist that will frequently have just played items in it - I used to shuffle once or twice a year - now its once or twice a week - altho - the phone seems to work better but I still have to shuffle more regularly on the iMac - I have tried splitting my library into two and asking it to shuffle library 1 or 2 and that is hit or miss usually defaulting to Apple Music with something I dont want to hear - I also tried the my music playlist which seems to be a playlist it creates and repeats but it is not of significant quantity to not make those repeats repetitive quickly - many more frustrations but you get the point - allowing random shuffles to play whatever playlist and the only command Siri seems recognize is “skip the song!” Pretty frustrating to say the least - I had hopes of finding a universal solution here but see that we are all in the same boat - LoL - I hear that crossfade is finally coming when I thought it was available all along - did I miss something - even tho it doesn’t seem to work it does allow you to set it - mine is currently at 12 seconds and yet I still get pauses between songs or have to say again “skip the song” due to a long pause between them!!!
Crossfade has always been available on the computer versions of iTunes or Music but not on the iPhone which is coming in the next iOS as you mentioned. This is why I have used Onkyo’s HF Player on my iPhone for many years since it has a crossfade function but you can’t set the time duration.
I have it set to 12 seconds overlap and gaps between songs lead to commanding Siri to “skip the song” which works about half the time - I never have any overlap or fad out to fad in - just me I guess but it doesn’t work?